Production of C2+ Olefins

ABSTRACT

This disclosure relates to the production of C 2+  olefins from feeds containing methane and at least one co-reactant, to equipment and materials useful in such processes, and to the use of such olefins in, for example, the production of polymers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Ser. No. 61/912,886, filed Dec.6, 2013, the disclosure of which is incorporated herein by reference inits entirety. This application also claims priority to EP 14153944.5,filed Feb. 5, 2014. Cross reference is made to the following relatedpatent applications: (i) P.C.T. Patent Application No. ______, (DocketNo. 2013EM331PCT), filed Nov. 17, 2014; (ii) U.S. patent applicationSer. No. ______, (Docket No. 2013EM331/2US), filed Nov. 17, 2014; (iii)P.C.T. Patent Application No. ______, (Docket No. 2013EM342PCT), filedNov. 17, 2014; (iv) U.S. patent application Ser. No. ______, (Docket No.2013EM330/2US), filed Nov. 17, 2014; (v) P.C.T. Patent Application No.______, (Docket No. 2014EM068PCT), filed Nov. 17, 2014; (vi) U.S. patentapplication Ser. No. ______, (Docket No. 2014EM068/2US), filed Nov. 17,2014; (vii) P.C.T. Patent Application No. ______, (Docket No.2013EM343PCT), filed Nov. 17, 2014; and (viii) U.S. patent applicationSer. No. ______, (Docket No. 2013EM343/2US), filed Nov. 17, 2014.

FIELD

This disclosure relates to the production of C₂₊ olefins from feedscontaining methane and at least one co-reactant, to materials andequipment useful in such processes, and to the use of such olefins in,for example, the production of polymers.

BACKGROUND

Although methane is abundant, its relative inertness has limited itsutility in conversion processes for producing higher-value hydrocarbons.For example, oxidative coupling methods generally involve highlyexothermic and potentially hazardous methane combustion reactionsfrequently require expensive oxygen generation facilities and producelarge quantities of environmentally sensitive carbon oxides.Non-oxidative methane conversion is equilibrium-limited, andtemperatures ≧about 800° C. are needed for methane conversions greaterthan a few percent.

Catalytic processes have been proposed to co-convert methane andethylene to higher hydrocarbons. For example, a process disclosed inHeterocyclic Dissociation of C—H Bond of Methane over Ag ⁺-exchangedZeolites and Conversion of Methane into Higher Hydrocarbons in thePresence of Ethene or Benzene, T. Baba and K. Inazu, Chemistry Letters,35 (2), 142-147, 2006, involves the heterocyclic dissociation of methaneover silver cationic clusters in Ag⁺-exchanged zeolites in the presenceof an ethylene co-feed. The dissociation leads to the formation ofsilver hydride and methyl cations, which react with the ethylene co-feedto produce propylene.

Since ethylene is itself a valuable hydrocarbon, processes are desiredwhich produce higher molecular weight unsaturated hydrocarbons frommethane without the need for unsaturated co-reactants, such as ethylene.It would also be beneficial if such processes did not produce largeamounts of low-value saturated hydrocarbon (e.g., ethane) and could beoperated such that the relative amounts of C₂ unsaturates and C₃unsaturates in the product are adjustable.

SUMMARY

The invention relates to the production of C₂₊ olefin, particularlyethylene and propylene, from feeds containing methane and otherhydrocarbons. It has been found that by contacting a feed containingmethane and one or more of (i) C₂₊ alkane, (ii) syngas, and (iii)alcohol, with at least one molecular sieve, high conversion to C₂₊olefin is achieved at relatively low reaction temperatures (e.g.,temperatures≦700° C.). In addition, it has been found that utilizingrelatively high space velocities favor the production of olefins ratherthan aromatics. The molecular sieve can comprise, e.g., at least onesmall pore zeolite, such as zeolite having a geometric mean of thecross-sectional dimensions of the pores ≦5.3 Å.

It is observed that when a feed comprising methane and the specifiedco-reactant reacts in the presence of at least one small-pore molecularsieve catalyst, the reaction's product includes (i) at least 5 wt. % ofC₂₊ olefin, based on the weight of the product, and (ii) molecularhydrogen.

In one aspect, the invention relates to a process for producing C₂+olefin from a feed comprising at least 9 mole % of methane and at least4% of the specified co-reactant, the mole percents being per mole of thefeed. The process includes contacting the feed with a catalystcomprising at least one molecular sieve, the molecular sieve comprisingat least one set of pores of substantially uniform size extendingthrough the molecular sieve, wherein geometric mean of thecross-sectional dimensions of each of the pores is less than or equal to5.3 Å. The contacting conditions can include, e.g., exposing thecatalyst and feed to a temperature≦700° C., to convert at least part ofthe methane and co-reactant in the feed to a product comprising C₂₊olefin. The process further includes separating at least part of the C₂₊olefin from the product, e.g., for storage and/or further processing.Non-limiting examples of suitable molecular sieves include thoseselected from the group consisting of CHA, AEL, AEI, LEV, AFX, ERI, TON,MTT, FER, MFS, and MWW framework type molecular sieves and mixturesthereof.

The co-reactant optionally comprises ethane and/or propane, for example,such that the feed comprises from 40 mole % to 95 mole % methane andfrom 5 mole % to 60 mole % ethane and/or propane; the mole percentsbeing per mole of the feed. The feed may be derived from natural gas.The contacting conditions can optionally include a feed gas hourly spacevelocity of at least 200 cm³/h/g of catalyst, such as at least 2000cm³/h/g of catalyst, for example at least 4000 cm³/h/g of catalyst.

DETAILED DESCRIPTION Definitions

For the purpose of this description and appended claims, the followingterms are defined. The term “C_(n)” hydrocarbon wherein n is a positiveinteger, e.g., 1, 2, 3, 4, or 5, means a hydrocarbon having n number ofcarbon atom(s) per molecule. The term “C_(n+)” hydrocarbon wherein n isa positive integer, e.g., 1, 2, 3, 4, or 5, means hydrocarbon having atleast n number of carbon atom(s) per molecule. The term “hydrocarbon”encompasses mixtures of hydrocarbon having different values of n. Forexample, the term C₁₊ hydrocarbon encompasses methane and ethane. Theterm “C_(n)−” hydrocarbon wherein n is a positive integer, e.g., 1, 2,3, 4, or 5 hydrocarbon having no more than n number of carbon atom(s)per molecule. For example, the term C³⁻ hydrocarbon encompasses methane,ethane, and propane. The term “syngas” means a mixture comprising atleast 12.0 mole % of molecular hydrogen and at least 0.4 mole % ofcarbon monoxide, per mole of the mixture.

As used herein, the numbering scheme for the groups of the PeriodicTable of the Elements is as disclosed in Chemical and Engineering News,63(5), 27 (1985).

Direct Conversion of Methane to Olefins

In certain aspects, the invention relates to a process for catalyticallyproducing olefins from a feed comprising methane and at least oneco-reactant. The co-reactant can comprise one or more of C₂₊ alkane,syngas and alcohol. Examples of certain feeds will now be described inmore detail. The invention is not limited to the use of such feeds, andthis description is not meant to foreclose the use of other feeds withinthe broader scope of the invention.

The process can employ a feed that is primarily in the vapor phase. Forexample, the feed can comprise of at least 9 vol. %, such as at least 25vol. %, for example, at least 40 vol. %, and, in some aspects up to 96vol. % of methane, and at least 4 vol. %, such as at least 10 vol. %, ofco-reactant, the volume percents being based on the volume of the feed.Optionally, the feed has a molar ratio of methane to co-reactant in therange of from 0.1:1 to 20:1, such as from 1:1 to 15:1, for example, from2:1 to 7:1.

Optionally, the feed further comprises ≧0.1 vol. % diluent, based on thevolume of feed. Diluent generally comprises species which do not reactin significant amounts with the methane or co-reactant under thespecified operating conditions. Suitable diluent includes one or more ofmolecular hydrogen, carbon dioxide, hydrogen sulfide, and molecularnitrogen. In certain aspects, the feed comprises diluent in an amount inthe range of from 0.1 vol. % to 50 vol. %, based on the volume of feed.Where present, some or all of the diluent can be present as by-productsof the process used to produce the feed's methane and/or co-reactant,e.g., as by-products of a natural gas purification stage.

C₂₊ Alkane Co-Reactant

In certain aspects, the co-reactant comprises C₂₊ alkanes, e.g., ≧90.0mole % of C₂₊ alkanes, per mole of the co-reactant, such as ≧99.0 mole%. Examples of suitable C₂₊ alkanes include those having a criticaldiameter less than that of benzene. The C₂₊ alkane can comprise ≧31 mole% of a mixture of ethane and propane, per mole of the C₂₊ alkane, e.g.,≧57 mole %, such as ≧80 mole %, or ≧98 mole %. Optionally, the C₂₊alkane comprises (i) ≧35 mole % of ethane, e.g., ≧62 mole %, such as ≧83mole %, or ≧98 mole %; or (ii) ≧27 mole % of propane, e.g., ≧52 mole %,such as ≧77 mole %, or ≧97 mole %; the mole percents being based permole of the C₂₊ alkane. In certain aspects, the feed is in the vaporphase and comprises from 40 vol. % to 95 vol. %, such as 60 vol. % to 90vol. % methane, and 5 vol. % to 60 vol. % C_(3—) alkane, such as from 10vol. % to 40 vol. % of a mixture of ethane and propane. The volumepercents being per volume of feed.

While not wishing to be bound by any theory or model, it is believe thatwhen the co-reactant includes propane, a representative reaction betweenmethane and propane to form C₂₊ olefins is as follows:

6CH₄+C₃H₈→C₂H₄+C₃H₆+C₄H₈+7H₂

Suitable feeds comprising C₂₊ alkanes as a co-reactant can be derivedfrom natural gas. Raw natural gas recovered at a well head usuallycontains impurities and contaminants including water vapor, hydrogensulfide, carbon dioxide, nitrogen, and other compounds. It is generallydesirable to purify the raw gas before deriving the feed (e.g., themethane and/or co-reactant). Purification can be carried out by anyconvenient method, including one or more of hydrogenation,dehydrogenation, sulfur, and acid gas removal techniques. Desired feedcomponents, e.g., methane and/or co-reactant, can then be separated fromthe purified natural gas by any convenient separation, e.g.,conventional separation methods such as fractionation. Optionally, thefeed is derived from a purified natural gas, which contains impuritiessuch as nitrogen compounds, sulfur compounds and carbon oxides in anaggregate amount that is ≦1.0 wt. %, based on the weight of the purifiednatural gas, e.g., ≦0.1 wt. %. Optionally, the natural gas is wetnatural gas. Besides methane, wet natural gas contains a significantamount of C₂ to C₅ alkane, which provides a convenient source of methaneand co-reactant, generally within the specified methane:co-reactantmolar ratio for the feed without the need for adjusting the relativeamounts of these molecules in the natural gas before deriving the feed.

Aspects of deriving the feed from natural gas will now be described inmore detail. The invention is not limited to these aspects, and thisdescription is not meant to foreclose other aspects for deriving thefeed within the broader scope of the invention.

Oil and gas can be obtained from a well reservoir, which includestrapped oil and gas within rock formations. One form of an oil and gaswell reservoir includes at least one subsurface pool of hydrocarbonscontained in porous sedimentary rock. A layer of impermeable rockformations, termed cap rock, generally prevents the escape of thenaturally occurring hydrocarbons into overlying sediment and rockformations (the overburden). Various recovery methods may be implementedto extract and recover both the oil and gas hydrocarbons. Duringrecovery, the oil and gas reservoir may produce the crude oil and rawnatural gas along with other liquid, gaseous, and solid hydrocarbons.

A hydrocarbon stream can be produced from the reservoir, the hydrocarbonstream generally including natural gas, oil, water, and combinationsthereof. The hydrocarbon stream can be flowed into a gas-oil separatorfor separating from the hydrocarbon stream at least one raw natural gasstream, at least one oil stream, and optionally streams comprising oneor more of other liquids. The raw natural gas can be further processedin one or more purification stages, to produce a purified natural gas.By-products from the purification stage, e.g., one or more of sulfurcompounds, including one or more of hydrogen sulfide mercaptans,sulfides, and other organosulfur compounds, water, trace metals, andentrained liquids and solids, can be conducted away.

Syngas Co-Reactant

In certain aspects the co-reactant comprises syngas e.g., ≧97 mole % ofsyngas, based on per mole of the co-reactant, such as ≧99 mole %. Thesyngas can comprise, e.g., molecular hydrogen and ≧0.4 mole % of carbonmonoxide, based on per mole of the syngas, and the syngas can have anH₂: (CO+CO₂) molar ratio in the range of from 0.5 to 20, such as anH₂:CO molar ratio in the range of from 0.5 to 20, or 0.6 to 10, or 0.8to 4. The syngas can be produced, e.g., from methane and/or othercarbon-containing source material. The type of carbon-containing sourcematerial used is not critical. The source material can comprise, e.g.,methane and other lower (C₄−) alkanes, such as contained in a naturalgas stream, or heavier hydrocarbonaceous materials, such as coal andbiomass. Desirably, the source material comprises ≧10 vol. %, such as≧50 vol. %, based on the volume of the source material, of at least onehydrocarbon, especially methane.

The source material can be converted to syngas by any convenient method,including those well-established in the art. Suitable methods includethose described in U.S. Patent Application Publication Nos. 2007/0259972A1, 2008/0033218 A1, and 2005/0107481 A1, each of which is incorporatedby reference herein in its entirety.

For example, natural gas can be converted to syngas by steam reformingThe first step normally involves the removal of inert components in thenatural gas, such as nitrogen, argon, and carbon dioxide. Natural gasliquids can also be recovered and directed to other processing ortransport. The purified natural gas is then contacted with steam in thepresence of a catalyst, such as one or more metals or compounds thereofselected from Groups 7 to 10 of the Periodic Table of the Elementssupported on an attrition resistant refractory support, such as alumina.The contacting is normally conducted at high temperature, such as in therange of from 800° C. to 1100° C., and pressures ≦5000 kPa. Under theseconditions, methane converts to carbon monoxide and hydrogen accordingto reactions, such as:

CH₄+H₂O =CO+3H₂.

Steam reforming is energy intensive in that the process consumes over200 kJ/mole of methane consumed. A second method is partial oxidation,in which the methane is burned in an oxygen-lean environment. Themethane is partially-oxidized to carbon monoxide (reaction (i)), with aportion of the carbon monoxide being exposed to steam reformingconditions (reaction (ii)) to produce molecular hydrogen and carbondioxide, according to the following representative reactions:

CH₄+ 3/2O₂=CO+2H₂O   (i),

CO+H₂O+H₂O=CO₂+H₂   (ii).

Partial oxidation is exothermic and yields a significant amount of heat.Because one reaction is endothermic and the other is exothermic, steamreforming and partial oxidation is often performed together forefficient energy usage. Combining the steam reforming and partialoxidation yields a third process wherein the heat generated by thepartial oxidation is used to drive the steam reforming to yield syngas.

In certain embodiments, the co-reactant comprises alcohol, e.g., C₁₊alcohol, such as methanol. For example, the co-reactant can comprise≧90.0 wt. % alcohol, based on the weight of the co-reactant, e.g., 99.0wt. %.

Alcohol co-reactant can be produced from syngas, for example. In certainaspects, syngas cis catalytically converted to alcohol, e.g., C₁₊alcohol, such as methanol. Conventional alcohol synthesis processes canbe used, but the invention is not limited thereto. In one aspect, theconversion of syngas to methanol is carried out at very highselectivities using a mixture of copper, zinc oxide, and alumina at atemperature of 200° C. to 400° C. and pressures of 50-500 atm. Inaddition to Cu/ZnO/Al₂O₃, other catalyst systems suitable for methanolsynthesis include Zn(VCr₂O₃, Cu/ZnO, Cu/ZnO/Cr₂O₃, Cu/ThO₂, Co/S, Mo/S,Co/Mo/S, Ni/S, Ni/Mo/S, and Ni/Co/Mo/S. The alcohol synthesis can becarried out separately from (e.g., upstream of) the specified conversionof methane to C₂₊ olefin, but this is not required. In certain aspects,methanol synthesis is carried out substantially simultaneously with thespecified conversion of methane to C₂₊ olefin, e.g., by (i) utilizingsyngas as a co-reactant and (ii) including at least onealcohol-synthesis functionality in the specified C₂₊ olefin synthesiscatalyst.

Combined Co-Reactant

In certain aspects, the co-reactant comprises C₂₊ alkane and alcohol,e.g., ≧7 mole % of C₂₊ alkane and ≧64 mole % of methanol, the molepercents being based on per mole of the co-reactant. Example, theco-reactant can comprise a mixture of C₂₊ alkane and methanol, themixture having a C₂₊ alkane:methanol weight ratio of 0.1 to 10.0, e.g.,in the range of 0.5 to 5.0.

Molecular Sieve Catalyst for C₂₊ Olefin Synthesis

The reaction of the methane with the specified co-reactant to produceC₂₊ olefin is conducted in the presence of a catalyst comprising atleast one small pore molecular sieve. Certain representative molecularsieves will now be described in more detail. The invention is notlimited to these molecular sieves, and this description is not meant toforeclose the use of other molecular sieves within the broader scope ofthe invention.

In certain aspects, the small pore molecular sieve include those havingat least one set of pores of substantially uniform size extendingthrough the molecular sieve, wherein geometric mean of thecross-sectional dimensions of each of the pores is less than or equal to5.3 Å. Examples of suitable molecular sieves include those having theframework types CHA, AEL, AEI, LEV, AFX, ERI, TON, MTT, FER, MFS, andMWW (see “Atlas of Zeolite Framework Types”, eds. Ch. Baerlocher, L. B.McCusker, D. H. Olson, Elsevier, Sixth Revised Edition, 2007, which ishereby incorporated by reference). For example, MWW framework typemolecular sieves have two sets of pores, each defined by 10-ringchannels, extending through the molecular sieve, wherein the pores ofone set having cross-sectional dimensions of 5.5 Å×4.0 Å (geometric mean4.7 Å) and the pores of the other set having cross-sectional dimensionsof 5.1 Å×4.1 Å (geometric mean 4.6 Å). Thus, the geometric mean of thecross-sectional dimensions of all the pores defined by these 10-ringchannels in MWW zeolites is less than or equal to 5.3 Å. The large (7.1Å diameter) surface pockets of MWW zeolite are not pores extendingthrough the molecular sieve and so are not considered in thiscalculation. Other molecular sieves that can be used in the presentprocess for converting methane and C₂₊ alkanes to C₂₊ olefins includethose having the framework types CHI, LOV, NAB, NAT, RSN, STT, and VSV.

Aluminosilicate molecular sieves are within the scope of the invention.Examples of suitable aluminosilicate molecular sieves include ZSM-22(described in U.S. Pat. No. 4,556,477), ZSM-23 (described in U.S. Pat.No. 4,076,842), ZSM-35 (described in U.S. Pat. No. 4,016,245), ZSM-57(described in U.S. Pat. No. 4,873,067), MCM-22 (described in U.S. Pat.No. 4,954,325), PSH-3 (described in U.S. Pat. No. 4,439,409), SSZ-25(described in U.S. Pat. No. 4,826,667), ERB-1 (described in EuropeanPatent No. 0293032), ITQ-1 (described in U.S. Pat. No. 6,077,498), ITQ-2(described in International Patent Publication No. WO 97/17290), MCM-36(described in U.S. Pat. No. 5,250,277), MCM-49 (described in U.S. Pat.No. 5,236,575), MCM-56 (described in U.S. Pat. No. 5,362,697), UZM-8(described in U.S. Pat. No. 6,756,030), and mixtures thereof.

Silicoaluminophosphate molecular sieve is also within the scope of theinvention. Examples of suitable silicoaluminophosphate molecular sieveinclude SAPO-34 (described in U.S. Pat. No. 4,440,871), SAPO-11(described in U.S. Pat. No. 4,440,871), SAPO-17 (described in U.S. Pat.No. 4,440,871), SAPO-18 (described by Chen et al in Catalysis Letters,28, 241-248 (1994)), SAPO-35 (described in U.S. Pat. No. 4,440,871),SAPO-56 (described in U.S. Pat. No. 5,370,851) and mixtures thereof.Mixtures of aluminosilicates and silicoaluminophosphates may also beemployed.

The catalyst employed to convert the methane/co-reactant mixture to C₂₊olefin generally further comprises at least 0.1 wt. %, such as from 0.1to 5 wt. %, of at least one dehydrogenation component. Thedehydrogenation component may comprise (i) one or more neutral metalsselected from Ag, Mo, Zn, La, Re, Co, Cu, W, Fe, Ni, Pt, Pd, In, and Gaand/or one or more oxides, sulfides and/or carbides of these metals. Thedehydrogenation component can be provided on the catalyst by anyconvenient method, including conventional methods. For example, thedehydrogenation component can be provided on the catalyst byimpregnation of the molecular sieve with a solution of a compound of therelevant metal, followed by conversion of the metal compound to thedesired form, namely neutral metal, oxide, sulfide and/or carbide.

Molecular sieve composites are within the scope of the invention. Forexample, the molecular sieve can be composited with another materialwhich is resistant to the temperatures and other conditions employed inthe conversion reaction. Such materials include active and inactivematerials and synthetic or naturally occurring zeolites as well asinorganic materials such as clays and/or oxides such as alumina, silica,silica-alumina, zirconia, titania, magnesia or mixtures of these andother oxides. The latter may be either naturally occurring or in theform of gelatinous precipitates or gels including mixtures of silica andmetal oxides. Clays may also be included with the oxide type binders tomodify the mechanical properties of the catalyst or to assist in itsmanufacture. Use of a material in conjunction with the molecular sieve,i.e., combined therewith or present during its synthesis, which itselfis catalytically active may change the conversion and/or selectivity ofthe catalyst. Inactive materials suitably serve as diluents to controlthe amount of conversion so that products may be obtained economicallyand orderly without employing other means for controlling the rate ofreaction. These materials may be incorporated into naturally occurringclays, e.g., bentonite and kaolin, to improve the crush strength of thecatalyst under commercial operating conditions and function as bindersor matrices for the catalyst. For example, the relative proportions ofmolecular sieve and inorganic oxide can be in the range of from about 1to about 90 percent by weight, typically, in the range of about 2 toabout 80 wt. % of the composite—particularly when the composite isprepared in the form of beads.

The feed and catalyst are exposed to reaction conditions effective forconverting the feed's methane and co-reactant to C₂₊ olefin.Representative reaction conditions will now be described in more detail.The invention is not limited to these reaction conditions, and thisdescription is not meant to foreclose other reaction conditions withinthe broader scope of the invention.

In certain aspects, a feed comprising methane and co-reactant is reactedin the presence of the specified catalyst to produce C₂₊ olefins, wherethe reaction conditions include one or more of (i) exposing the methaneand co-reactant to a temperature of no more than 700° C., such as in therange of from 400° C. to 700° C., (ii) at a pressure in the range offrom 1 bar (absolute) to 5 bar (absolute) (100 to 500 kPa absolute), and(iii) gas hourly space velocity ≧200 cm³/h/g of catalyst, such as ≧2000cm³/h/g of catalyst, for example ≧4000 cm³/h/g of catalyst. For example,the reaction conditions include (i) exposing the methane and co-reactantto a temperature in the range of from 450° C. to 650° C., (ii) apressure in the range of from 2 bar (absolute) to 4 bar (absolute) (200to 400 kPa absolute), and (iii) gas hourly space velocity in the rangeof from 200 cm³/h/g of catalyst, to 20,000 cm³/h/g of catalyst, e.g.,500 cm³/h/g of catalyst, to 5,000 cm³/h/g of catalyst. When theco-reactant includes ≧86 mole % of syngas, based on per mole of theco-reactant, the molecular sieve preferably includes SAPO-34 and/orChabazite.

Without wishing to be bound by a theory of operation, it is believedthat olefins, which can be precursors for the production of aromatics,will convert into aromatics if allowed to be in contact with thecatalyst for longer times. In addition, it is believed that selectiveproduction of olefins over aromatics can be favored not only by sizeselectivity of the molecular sieve catalyst but also by operating athigh space velocity. The preferred space velocity range depends on thecatalyst, feed and temperature used. Some representative gas hourlyspace velocities (GHSV) for catalysts operating in the range from 400°C.-700° C. are in the range from 2000-25000 cm³/g/h, preferably15000-25000 cm³/g/h.

The methane conversion process can be conducted in one or more fixedbed, moving bed or fluidized bed reaction zones. The process can beoperated continuously, semi-continuously, or in batch mode.

The methane conversion reaction tends to deposit coke on the catalystand hence, to maintain the activity of the catalyst, at least part ofthe catalyst can be continuously or intermittently regenerated. This maybe achieved by withdrawing a portion of the catalyst from the or eachreaction zone, either on an intermittent, or a continuous basis, andthen transferring the catalyst to a separate regeneration zone. In theregeneration zone, the coked catalyst may be contacted with ahydrogen-containing gas under conditions effective to convert at least aportion of the carbonaceous material on the catalyst to methane, whichcan then be recycled back to the conversion reaction. In one embodiment,the hydrogen required for the regeneration is obtained at least in partfrom the hydrogen-containing effluent from the methane conversionreaction.

Depending on the conditions and catalyst employed, at least 1%, such asfrom 5% to 50%, of the methane in the feed (on a weight basis) isconverted to a product mixture comprising C₂₊ olefin. Generally, themolar ratio of olefins to aromatics in the product mixture is greaterthan 0.5:1, more preferably greater than 1:1, more preferably greaterthan 10:1. The distribution of light olefins in the C₂₊ unsaturatedproduct depends on operating conditions, the pore size and acid activityof the molecular sieve, with SAPO-34 and SAPO-56 tending to produce thehighest selectivity to ethylene and propylene.

The C₂₊ olefin can readily be removed from the other conversionproducts, such as hydrogen, and any residual methane and co-reactant byany convenient method, e.g., by conventional separation methods.

The C₂₊ olefin produced by the present process can be used as feedstockin a variety of important industrial processes, including the productionof homopolymers and copolymers of ethylene and propylene.

All patents, test procedures, and other documents cited herein,including priority documents, are fully incorporated by reference to theextent such disclosure is not inconsistent and for all jurisdictions inwhich such incorporation is permitted.

While the illustrative forms disclosed herein have been described withparticularity, it will be understood that various other modificationswill be apparent to and can be readily made by those skilled in the artwithout departing from the spirit and scope of the disclosure.Accordingly, it is not intended that the scope of the claims appendedhereto be limited to the examples and descriptions set forth herein butrather that the claims be construed as encompassing all the features ofpatentable novelty which reside herein, including all features whichwould be treated as equivalents thereof by those skilled in the art towhich this disclosure pertains.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated,and are expressly within the scope of the invention. The term“comprising” is synonymous with the term “including”. Likewise whenevera composition, an element or a group of components is preceded with thetransitional phrase “comprising”, it is understood that we alsocontemplate the same composition or group of components withtransitional phrases “consisting essentially of,” “consisting of”,“selected from the group of consisting of,” or “is” preceding therecitation of the composition, component, or components, and vice versa.

1. A process for producing one or more of C₂₊ olefin, the processcomprising: (a) providing a feed comprising at least 9 vol. % of methaneand at least 4 vol. % of at least one co-reactant selected from thegroup consisting of C₂₊ alkane, syngas, and alcohol; (b) providing acatalyst comprising at least one molecular sieve, the molecular sievecomprising at least one set of pores of substantially uniform sizeextending through the molecular sieve, wherein geometric mean of thecross-sectional dimensions of each of the pores is less than or equal to5.3 Å; (c) contacting the feed with the catalyst under conditions,including a temperature of no more than 700° C., effective to convert atleast part of the methane and co-reactant in the feed to a productcomprising C₂₊ olefin; and (d) separating at least part of the C₂₊olefin from the product.
 2. The process of claim 1, wherein the at leastone molecular sieve comprises an aluminosilicate molecular sieve and/ora silicoaluminophosphate molecular sieve.
 3. The process of claim 1,wherein the at least one molecular sieve is selected from the groupconsisting of CHA, AEL, AEI, LEV, AFX, ERI, TON, MTT, FER, MFS, and MWWframework type molecular sieves and mixtures thereof.
 4. A process forproducing C₂₊ olefin, the process comprising: (a) providing a feedcomprising at least 9 vol. % of methane and at least 4 vol. % of atleast one co-reactant selected from the group consisting of C₂₊ alkane,syngas, and alcohol; (b) providing a catalyst comprising at least onemolecular sieve selected from the group consisting of CHA, AEL, AEI,LEV, AFX, ERI, TON, MTT, FER, MFS, and MWW framework type molecularsieves and mixtures thereof; (c) contacting the feed with the catalystunder conditions, including a temperature of no more than 700° C.,effective to convert at least part of the methane and co-reactant in thefeed to a product comprising C₂₊ olefin; and (d) separating at leastpart of the C₂₊ olefin from the product.
 5. The process of claim 4,wherein the at least one molecular sieve is selected from the groupconsisting of Chabazite, SAPO-34, SAPO-11, SAPO-18, SAPO-35, SAPO-56,SAPO-17, ZSM-11, ZSM-23, ZSM-35, ZSM-57, MCM-22, ZSM-49, ZSM-56 andmixtures thereof.
 6. The process of claim 4, wherein the catalystcomprises at least 0.1 wt % of at least one dehydrogenation componentbased on the weight of the catalyst.
 7. The process of claim 6, whereinthe dehydrogenation component comprises (i) one or more neutral metals,(ii) one or more metal oxides, (iii) one or more metal sulfides and/or(iv) one or more metal carbides.
 8. The process of claim 7, wherein thehydrogenation metal comprises at least one of Ag, Mo, Zn, Re, Cu, La,Co, W, Fe, Ni, Pt, Pd, In, and Ga.
 9. The process of claim 4, whereinmolar ratio of methane to co-reactant in the feed is from 0.1:1 to 20:1.10. The process of claim 4, wherein the molar ratio of methane toco-reactant in the feed is in the range of from 1:1 to 15:1.
 11. Theprocess of claim 4, wherein the molar ratio of methane to co-reactant inthe feed is in the range of from 2:1 to 7:1.
 12. The process of claim 4,wherein the feed is derived from natural gas.
 13. The process of claim4, wherein the conditions in (c) include a temperature in the range offrom 400° C. to 700° C. and a pressure from 1 bar (absolute) to 5 bar(absolute) (100 to 500 kPa) (absolute).
 14. The process of claim 4,wherein the conditions in (c) include a gas hourly space velocity of atleast 200 cm³/h/g of catalyst.
 15. The process of claim 4, wherein from5% to 50% of the methane in the feed is converted in step (c).
 16. Theprocess of claim 4, wherein the molar ratio of olefins to aromatics inthe product is greater than 0.5:1.
 17. The process of claim 4, whereinthe co-reactant comprises 98 mole % of C₂₊ alkane, based on per mole ofthe co-reactant.
 18. The process of claim 4, wherein the feed comprisesfrom 40 vol. % to 95 vol. % methane and from 5 vol. % to 60 vol. %ethane and/or propane.
 19. The process of claim 4, wherein theco-reactant comprises 99.0 vol. % of alcohol, based on the volume of theco-reactant.
 20. The process of claim 19, wherein the alcohol isproduced from syngas.
 21. A process for producing a polyolefin, theprocess comprising polymerizing at least one C₂₊ olefin produced by theprocess of claim 4.